Synthesis and evaluation of corrosion inhibiting activity of new molecular hybrids containing the morpholine, 1,4-naphthoquinone, 7-chloroquinoline and 1,3,5-triazine cores

Three molecules containing morpholine, 1,4-naphthoquinone, 7-chloroquinoline and 1,3,5-triazine cores, scaffolds with recognized anti-corrosive activity, were synthesized and had their anticorrosive activity evaluated through potentiodynamic polarization and electrochemical impedance studies. Both studies were conducted in a simulated production water medium containing 150,000 mg·L-1 Cl- and 5 mg·L-1 S2-. Corrosion inhibition efficiency ranged from 67% - 86%, amongst which the naphthoquinone-containing derivative (compound 1) was the most effective. These compounds act through formation of a protective film on the surface of AISI 316 stainless steel. Investigation of the molecular properties of the prepared inhibitors by DFT calculations revealed that the LUMO energy and chemical hardness of the molecules can be directly correlated with their inhibition efficiency

Nitração aromática: substituição eletrofílica ou reação com transferência de elétrons? Aromatic nitration: electrophilic substitution or reaction with electron transfer?

<abstract language="eng">Aromatic nitration is one of the most relevant class of reactions in organic chemistry. It has been intensively studied by both experimental, including works in the condensed as well as in the gas phase, and theoretical procedures. However, the published results do not seem to converge to an unique mechanism. Electrophilic substitution and electron transfer, in an exclusive way, are both proposed as the main mechanism for the reaction. We review these proposals and discuss the most recent findings

Structural characterization of unusually stable polycyclic ozonides.

The single crystal structure of seven tri- and tetracyclic ozonides derived from 8-oxabicycle[3.2.1]oct-6- en-3-ones have been characterized by X-ray diffraction method. Five ozonides (4, 5, 6, 7 and 8) crystallize in the monoclinic crystal system with P21/c space group. Compound 3 crystallize in the unusual centrosymmetric space group R_3m, which represents _0.04% of the total number of structures know. The supramolecular structure of 3 forms infinite channels in a hexagram fashion, resulting in a honeycomb- like structure. Semi-empirical (PM6) and density functional theory methods (DFT) with the B3LYP functional and the 6-31G(d) basis set were used to optimize the geometries and compute structural parameters (bond lengths, angles and dihedral angles) that could be compared to the refined crystal structure. The theoretical results show good agreements with the experimental structure

Synthetic naphthoquinone derivatives as anticancer agents in ovarian cancer: cytotoxicity assay and investigation of possible biological mechanisms action

In this study, eight naphthoquinone derivatives were synthesized in yields ranging from 52 to 96% using easy, fast, and low-cost methodologies. All naphthoquinone derivatives were screened for their in vitro anti-proliferative activities against OVCA A2780 cancer cell lines. Amongst all analysed compounds, derivatives 3–5 presented the most prominent cytotoxic potential. Naphthoquinones 3 and 4, bearing sulfur-containing groups, were identified as having high potential for ROS production, in particular the superoxide anion. Furthermore, 3 and 4 compounds caused a decrease in the cell population in G0/G1 and induced more than 90% of the cell population to apoptosis. Compound 5 did not act in any of these processes. Finally, compounds 3–5 were tested for their inhibitory ability against PI3K and MAPK. Compounds 3 and 4 do not inhibit the PI3K enzyme. On the other hand, the naphthoquinone-polyphenol 5 was only able to inhibit the percentage of cells expressing pERK